1. Field of the Invention
The present invention relates to an inkjet printer head, and more particularly to an apparatus and method for determining an initial position and protecting a capping release error in an inkjet printer head which can constitute a sensor for determining a printing initial position and a device for preventing a capping state from being released during the head is at a homestation, with a single sensor and two actuators.
2. Description of the Related Art
Generally, a printing machine, which performs a printing operation by mounting a head on a carriage, has adopt various methods for recognizing a current printing position of the head. As representative ones, there are a method for recognizing a reference position using an encoder and a method for memorizing a moving distance from a reference position by installing a home sensor at a predetermined position and thereby sensing a current position of the head.
The encoder utility method exhibits a problem in that a production cost is high because the encoder itself is expensive.
The home sensor installing method also exhibits a problem in that a production cost is high because a great number of stepping motors are used.
FIG. 1 is a schematic view showing a construction of a conventional initial position determining and capping release error protecting apparatus. In the construction, a home sensor 1 is mostly used with an optical sensor or microswitch, and a single actuator 2 is disposed at a carriage 3 and senses the home sensor 1 to thereby control a reference position.
Whenever the control for the reference position is executed during a printing operation, the home sensor 1 is adapted to be sensed to thereby avoid deviation of the reference position. So as to control the reference position during the printing operation, when the actuator 2 moves to the home sensor 1, the carriage 3 moves up to a servicestation 4, such that the carriage 3 becomes in contact with the components of servicestation 4, which results in generation of noises. Accordingly, the carriage 3 in the home sensor 1 position should set the reference position in such a manner that it is placed in left direction from a capping position.
The carriage 3 performs a round trip within a print interval, and the capping position moves toward a service interval by a distance determined on the basis of a mechanical design value after the home sensing is executed.
It is, however, difficult to prevent a capping release error with one home sensor 1 and one actuator 2, as shown in FIG. 1. Since a cap 5 made of a rubber material is structured to perform a capping operation within the interval (3 mm or more) where the cap 5 may be deviated during capping a nozzle 8, only one home sensor 1 and one actuator 2 have great difficulties in simultaneously sensing an initial position and a capping release error generation of the printer head.
Accordingly, a sensing device is needed for determining the initial position during the printing operation, and further a device for preventing a capping state from being released is required during the head 6 is at the servicestation 4. However, while the capping state is kept, if the head 6 is considerably moved toward the print interval due to an impact from the outside and unexpected external force and thus a capping release error is undesirably generated, it is impossible to return to the capping state, so that the nozzle 7 of the head 6 may be dried and will be finally blocked.